A 10% positive-area change allowed both contrast signs in 16 ERP CORE P3 records under a 40 ms delay control

We tested a half-area time score in 16 selected ERP CORE P3 records. For each record, two fixed waveform controls had a 40 ms numerical delay between them, and the score used a 300 to 600 ms sample window. Each control kept its positive area total and source positive peak limit. Independent cell changes that moved at most 10% of positive area allowed negative and positive time contrasts in every record. The exact bounds for the equal-record mean contrast were -32.07 to +64.28 ms; the mean source contrast was +14.56 ms. A proof, endpoint arrays, 960 independent linear programs, and an identical numerical repeat support the result. The 10% limit is an assumption. The model has no smoothness limit and does not constrain negative voltage. The test does not measure neural delay. Source-derived epochs, trial tables, and source metadata are omitted from the SCI package because the retained source license requires CC BY-SA 4.0; extraction code, results, figures, proofs, and provenance remain included.

ERP CORE · P3 · event-related potentials · area latency · half-area time · measurement sensitivity · EEG · positive area · exact bounds